On the flow characteristics of various jets over a flat plate submerged in a uniform stream


A numerical and an experimental flow visualization analysis have been conducted on the flow over a flat plate with a vertical pulsing jet located downstream of the leading edge. The resulting unsteady flow fields under constant or pulsing jets are obtained by solving the time-dependent full Navier-Stokes equations using a pressure-based algorithm and visualized in an open channel. A body fitting orthogonal grid system has been employed which allocates more grid points at the jet exit and also increases the density of the grid toward the flat plate where flow variables have large gradients. The effects of different combinations of Reynolds and Strouhal numbers and jet to free stream velocity ratios on the resulting flow fields have been examined. The results show that a vortex wake flow behind a constant jet appears as long as the jet velocity ratio exceeds 1.0 and the vortex shedding frequency is a function of both main flow Reynolds number and the jet velocity ratio. The resulting wake flow immediately assumes the forced frequency in the pulsing jet, but the wall shear rate amplitude depends markedly on the pulsing frequency. A qualitative comparison of the numerical results with the experimental results shows good agreement indicating that the parameters used in the numerical model were a good representation of the physical system.

Publication Title

American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED

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